1. Field of the Invention
The present invention relates to methods of forming electronic devices, and more particularly, to methods of forming storage nodes for capacitors and related structures.
2. Discussion of the Related Art
With increasing demands for higher-capacity and lower-power dynamic random access memories (DRAMs), methods have been proposed for increasing capacitance of memory cell capacitors while decreasing design rules. The capacitance of the capacitor is proportional to a facing area (hereinafter, referred to as a capacitor area) between an upper electrode (a plate electrode) and a lower electrode (a storage node) and a dielectric constant of a dielectric layer of the capacitor. The capacitance of the capacitor is inversely proportional to a thickness of the dielectric layer. Various kinds of storage nodes have been proposed to increase the capacitor area. Typically, the storage node can be formed in a cylindrical shape, and a height of the storage node can be increased to increase the capacitance of the capacitor.
FIG. 1 is a cross-sectional view illustrating conventional storage nodes. Referring to FIG. 1, an interlayer insulating layer 12 is formed on a semiconductor substrate 10, and storage node plugs 16 passing through the interlayer insulating layer 12 are connected with the semiconductor substrate 10. The storage node plugs 16 are electrically connected with active areas of respective transistors. An etch stop layer 14 remains on the interlayer insulating layer 12. The etch stop layer 14 is formed to reduce etching of the interlayer insulating layer 12 when forming the storage nodes. Respective storage nodes 4 are connected with the corresponding storage node plugs 16. The storage nodes 4 are typically formed in a cylindrical shape to increase the capacitor area. However, when forming high storage nodes, the storage nodes may be tilted. Accordingly, undesired contact may occur between adjacent storage nodes. In addition, planarization and interconnection processes may be difficult to perform.